Verifier



March 21, 1967 Original Filed Nov. 9. 1959 7 Sheets-Sheet 1 FIG. I

TYPEWR/TER KEYBOARD u/vmc/r LOCK FUNCT/ON SELECTOR RECORD L VERIFY gRECORD 100 2 2 VERIFY MP R MEMORY -10! D START STOP RECORD READ TAPEDR/VE HEADS MECHAN/SM INVENTORS HERBERT E WEZSH BY LOU/5 0. WILSONATTORNEY March 21, 1967 H. F. WELSH ETAL 3,310,787

VERIFIER Original Filed NOV. 9, 1959 '7 Sheets-Sheet 4 FIG. 2C

FIG. 2d

TAB

F/G 2a.

TR/P

COL 5/ KEYBOARD UNLOCK A C TUA TOR DEL/1 Y ON PICK-0P C04. 7 CR 7 CR8 CKREVZ a SPACE R RV 5w V T LM KEYBOARD LOCK REV REL/l Y Ac TUA TORINVENTORS HERBERT F. W61 SH A T TOR/V5 Y March 21, 1967 H. F. WELSH ETAL3,310,787

VERIFIER Original Filed Nov. 9, 1959 7 Sheets-Sheet 5 F1630. F|G.3b FIG.3c

FSR3

FIGAE REVI/ BKWD FRWD CAPSTAN MOTOR lZOms DELA Y 01v DROP our INVENTORJ'HERBERTF WELSH LOU/6 0. WILSON ATTORNEY March 21, 1967 H. F. WELSH ETALVERIFIER Original Filed Nov. 9, 1959 FIG.5

:ENCODING SWITCHES OUT PU T- TO GR/ OF COMPARATOR ERROR THY. 2d)

000 E Vf N CHE CKE R PROBE FROM RES TME CLEAR RE LA POLE MEM 0/? Y THYRATR 0N5 READ WRITE R w RELAYS /8 SPRE CH CH CH CH WRWRWRWRW '7Sheets-Sheet 6 L 35L SWITCH CH3 CH2 CH I INVENTORS HERBERT F WELSHLOU/.5 D. W/LSON A TTORNE Y March 21, 1967 H. F. WELSH ETAL 3,310,787

VERIFIER 7 Sheets-Sheet '7 Original Filed Nov. 9. 1959 RQQQE W MENINVENTORS HERBERT F. WEI. .S'H LOU/.5 0. W/[. SUN

A T TORNE Y United States Patent Ofifice 3,310,787 Patented Mar. 21,1967 3,310,787 VERIFIER Herbert Frazer Welsh, deceased, late ofPhiladelphia, Pa., by Julea S. Chapline, executrix, Philadelphia, Pa.,and Louis D. Wilson, Springfield Township, Montgomery County, Pa.,assignors to Sperry Rand Corporation, New York, N.Y., a corporation ofDelaware Contlnuation of application Ser. No. 851,849, Nov. 9, 1959.This application Apr. 23, 1965, Ser. No. 453,544 29 Claims. (Cl.340-1725) This is a continuation of US. patent application Ser. No.851,849, filed Nov. 9, 1959.

This invention relates to tape verifiers and in particular relates todevices for detecting and/or correcting errors recorded upon magnetictape.

In particular, this invention refers to magnetic tape verifiersutilizing a typewriter keyboard input, in combination with associatedcircuitry for performing verification.

Devices such as shown by U.S. Patent 2,860,325 are commerciallyavailable for recording magnetic impulses on tape in a coded formcorresponding to various character representations. These devices,generally, comprise a typewriter in combination with an encoder andrecorder so that, upon actuating the keyboard of the typewriter, avisual message is printed by the typewriter and a corresponding messageencoded by the recorder onto magnetic tape in the form of magnetizedimpulses.

The message recorded upon magnetic tape may be erroneous due tooperators errors, machine errors, or both. An operator may make an errorin that an improper character may be typed, a line duplicated, a lineinadvertently omitted, etc. A machine may make an error due tomechanical imperfections, such as a faulty line from the encoder due toopen circuits, etc. In addition, noise" may be recorded upon the tape inthe form of extraneous impulses to present an erroneous character.Generally, the errors may take any of the following forms: impropercharacter recorded, improper parity recorded, too many characters perline of tape recorded, and/ or too few charaeters per line recorded.

The messages recorded upon magnetic tape, generally, are of greatimportance so that accuracy of the recorded message is mandatory. In thepast, the accuracy of a tape was determined by having one operatorrecord a message on one tape and a second operator perform the same message on another tape. The two tapes were then compared for identity todetermine its accuracy. This method has certain undesirable features.First, it is required that two machines be used to reduce thepossibility of similar machine errors (if both machines contain the samekind of error, the error is recorded undetected). Second, when the tapesdo not compare, subsequent trials are required until two tapes arerecorded which compare identically with one another. Obviously, thissystem is both timeconsuming and expensive.

In addition, in the past, at least two reels of tape for each message tobe recorded were required.

It is an object of this invention to provide a novel verifier.

It is a further object of this invention to provide a novel magnetictape verifier.

It is a further object of this invention to provide a novei magnetictape recorded and verifier combination.

It is an object of this invention to provide a novel magnetic tapeverifier for comparing magnetic tape with a written message and forcorrecting errors on said tape.

In accordance with one embodiment of this invention, a message can berecorded upon magnetic tape by an operator, either by the use of amagnetic tape recorder or by the use of the recorder-verifier hereindescribed. This message is transcribed from a written or printed copy byan operator by the actuation of various keys of a keyboard.Subsequently, a second operator compares this tape with the printedmessage by the use of the verifier described hereinbelow and, in theevent of errors, corrects the errors that occur on the tape. In bothcases, during the original recording and during verification, theactuation of the keyboard actuates a typewriter to provide a visualrecord.

The device herein described has two primary functions. First, ifdesired, it can be used for recording information on tape from a sourcedocument. Second, it compares information on previously recorded tapeswith information typed from the original source material on a keyboardby an operator (the operator can correct detected errors).

Additional objects and advantages of this invention together with itsconstruction and mode of operation will be more apparent from thefollowing description, when read in connection with the accompanyingdrawings, in which various components are duplicated for simplicity ofillustration, and in which:

FIG. 1 is a simplified functional diagram useful for illustrating andexplaining a typical sequence of events which occur in the apparatus ofthe invention during a record or a verify operation;

FIGS. 2a, 2b, and 2c illustrate in detail the principal portions of oneembodiment of this invention;

FIG. 2d illustrates the format of FIGS. 2a, 2b, and 2c;

FIGS. 30, 3b, and 3c illustrate the various timing circuitry of severalof the components shown in FIG. 20;

FIGS. 4a, 4b, 4c, 4d, 42, and 4f are diagrams which show variousportions of one embodiment of this invention;

FIG. 5 is a schematic diagram which illustrates, in greater detail, aportion of the circuitry shown in FIG. 2a; and

FIG. 6 is a schematic diagram of the comparator-odd even checker shownin FIG. 5.

The recorder-verifier is, generally, a compact unit which is housed in adouble pedestal typewriter desk (not shown). A typewriter unit includingan encoding unit is mounted on a raised center section of the desk. Adouble depth drawer at the left side of the desk houses the tapetransfer mechanism and control panel. The power supply is housed in thelower section of the right pedestal. The electronic section is enclosedin back of the knee well of the desk so that the wiring and the tubesare easily accessible.

Referring to. the functional diagram of FIG. I, there is shown akeyboard which comprises a plurality of keys normally found on astandard typewriter keyboard and, in addition, various control keysincluding 120 correct (120 CRCT), change one line (COL), and display (RDOUT).

A manually operable function selector switch FS is provided forselecting the functions of record and verify. With the function selectorswitch set to the record position, the apparatus of the presentinvention is in the recording mode wherein information is encoded on amagnetic tape. In the herein-illustrated embodiment the informationappears on the tape as a seven bit binary code, as illustrated in US.Patent 2,860,325 supra. Upon actuation of a character key on thekeyboard, a character is imprinted on paper by the typewriter and acoded electrical signal representation of the character is generated.Also, a control electrical signal is coupled to a tape drive mechanismto start magnetic tape in motion. In actual practice, the tape isstarted in motion prior to the application of the coded electricalsignal representation to the tape record heads. To simply illustratethis sequence in FIG. 1, the coded output from the keyboard is shown asbeing applied to a record control circuit 700 from whence a controlsignal is applied through a buffer 701 to the start input of the tapemechanism 702 and thereafter the coded signal representation is appliedvia a cable 703 to the record heads 704. A second control signal delayedfrom the selected character representation signal is applied via line705 to the tape drive mechanism 702 to stop the tape. This process isrepeated so that subsequent characters actuated at the keyboard arerecorded upon the tape. Each character key actuated at the keyboardtypes a character on paper, starts the tape, records the encodedcharacter upon the tape, and stops the tape, in the order named.

To verify, the tape being subsequently rewound to a start position, byappropriate means not shown, the function selector is manually switchedto the verify position which causes a one-shot" multivibrator 706, ordelay flop, to generate a pulse to actuate the tape drive mechanism. Thecharacter representation previously recorded upon the tape is read bythe magnetic heads and stored in a memory 707. Another electricalcontrol signal delayed from the electrical representation read by themagnetic heads is coupled via the leads 708 and 709 to subsequently stopthe tape drive mechanism 702, which, in addition, unlocks the keyboardto permit actuation thereof by an operator. The operator strikes a key,corresponding to the character printed on the source material to becompared. The striking of the key causes the character to be typed inred ink on paper. An electrical character representation generated bythe keyboard and the representation stored in the memory are comparedfor identity by a comparator 710. An electrical control signal appearingon the line 711 in response to the actuation of the keyboard is furtherconnected to start the tape drive mechanism so that the subsequentcharacter on the tape can be read by the magnetic beads, stored in thememory, and coupled to the tape drive mechanism to stop the tape. Thecomparator, upon receiving an indication of non-comparison (i.e.,non-identity), produces an error signal on the line 712. This errorsignal is coupled to the keyboard to lock the keyboard from furtheractuation of printing keys by the operator.

It is noted that the keyboard, upon the striking of a key indicative ofa character to be printed, automatically locks and remains in lockedposition until the system is prepared to receive a subsequent actuationof a printing key.

OPERATING CHARACTERISTICS A recorder-verifier built in accordance withthe teachings of this invention, when recording, produces a pulsedensity of 50 pulses per inch, arranged in 120 digit blockettes, uponthe tape. Each blockette produced by the verifier measures 2.44 inches.Blockettes are separated by an unrecorded space approximately two incheslong. When used for verification, the recorder-verifier can accommodatetapes on a six inch reel, recorded in blockette form, with a pulsedensity of 50 pulses per inch.

The recorder'verifier can be adapted, by means not shown, for automaticloading and rewinding of tape.

An operator can type at a rate as high as twelve characters per second.A mechanical ball interlock system (not shown) is incorporated in thetypewriter to prevent the operation of two keys at once.

A 12-inch carriage travel enables 120 digits to be placed on a line. Aline guide with 120 numbered divisions indicates to th typist the digitposition at any point in the line. Each line of 120 digits is referredto as a blockette. When the carriage reaches the digit position 121, theoperator can operate a trip" key which prints an underscore and returnsthe carriage. As the carriage is returned, additional tape passes thehead to allow the two inch space between blockettes.

A block of information consists of six blockettes (720 digits) andoccupies approximately 26 inches on the tape (including the spacebetween blockettes). The space between blocks is the same as the spacebetween blockettes. The concept of a block of information is of noimportance for an understanding of this invention. It is mentionedherein for informative purposes.

Operation of a tab key (otherwise termed a fill key) causes the carriageto move to the next tabulation stop. The tabulation stops are manuallyset and function in a similar manner as on a standard typewriter. As thecarriage moves in a forward direction, the tape also moves acorresponding distance, and fill characters (e.g., zero or space, asdesired) are automatically recorded on the tape.

Operation of a skip fill key causes the carriage to tabulateautomatically to digit position 120, by-passing all set tabulator stops.As the carriage moves, the tape moves and records as during the filloperation.

A fill selector" key selects either zeros or space symbols to berecorded during a fill operation.

A backspace key moves the carriage and the tape backward, one digitspace at a time, permitting inspection of the information recorded onthe tape.

Operation of a carriage return key returns the carriage to the beginningof the line, advances the paper in the typewriter, and moves the tapebackward to the beginning of the blockette.

When a trip key is depressed at digit positions 121, it (1) prints anunderscore to indicate a trip operation, (2) returns the carriage, (3)moves the tape forward to provide space between blockettes and blocks,and (4) advances the paper. No information is recorded on the tapeduring a trip operation.

Verification is achieved by comparing, digit by digit, the informationon the tape with the text used in preparation of the tape. The operatorstrikes the key indicated by the original text. If the struck keycorresponds to the character stored in the memory, the character isprinted in red and the carriage and tape are spaced. If the op' eratorstrikes the wrong key or if the wrong character is recorded on the tape,printing occurs and the carriage is spaced; however, the keyboard locksand an error lamp lights. The operator can backspace and determine froma suitable display (not shown) the character that is recorded on thetape in the position in question. The operator can then either correctthe tape or reverify the character, depending upon whether the error ison the tape or is made by the operator.

Use of the fill key and previously set tab stops per mit the operator toskip past insignificant material Without verification. Each codecombination on the tape, as indicated in US. Patent 2,860,325, is givenan odd-even (parity) check during this operation. Failure to satisfythis check causes an error.

Each blockette is checked to determine its number of code combinations.If the number is other than 120, the keyboard locks and one of twolights or on the display panel lights, indicating whether the number isless than or greater than 120.

Corrections are made through the operation of a change-one-line (COL)key which switches the verifier temporarily to the record cycle ofoperation. Characters are typed in black ink during a change-one-lineoperation, and during a record operation. After corrections, anautomatic carriage return takes place; this blockette, then, must bereverified.

The trip and carriage return keys during the verify cycle function asduring the record cycle; however, during the verify cycle, the backspacekey is locked, except when a comparator error is detected.

AUTOMATIC CHECKS The keyboard is locked during the trip, carriagereturn, backspace, and tabulate operations in both the record and verifycycles.

During the verify cycle, each blockette is checked for the number ofcharacters in that blockette. Other than 120 digits in a blockettecauses the operation of the verifier to stop, and the error to beindicated by an appropriate lamp (greater or less than 120) on thedisplay panel.

During the verify cycle, the color of the printed copy serves as a checkfor the operator. Only properly verified characters appear in red.Characters corrected but not verified appear in black.

FUNCTIONAL DESCRIPTION The mode of operation of this invention isdescribed with reference to the accompanying drawings which illustratethe features of the machine without undue unnecessary detail. Thevarious relay poles illustrated in the drawings are shown in theirunactuated positions.

The relay coils are illustrated in the drawings as coils, appropriatelylegended to indicate their function, such as the record-verify relaycoil RV RLY, shown in FIG. 4b. The various poles associated with therelays are symbolically shown in the figures as encircled contacts withidentifying legends, indicating the particular pole associated with arelay, such as the pole RV-S shown in FIG. 40 which indicates the eighthpole associated with the record-verify relay.

Further, in the associated drawings, the various switches are shown ascontacts enclosed in rectangles.

The buffers are illustrated as semi-circles with a sign inscribedtherein to illustrate its logical function. The gate 6-! is illustratedas a semi-circle with a dot therein to indicate its logical function.

In the diagrams, a delay flop, also termed a one-shot multivibrator, isshown as a rectangular block labelled with an abbreviation symbol DF. Adelay flop has an input terminal, and has a set output and/or resetoutput. An output is present at the set output for a predeterminedperiod of time following the application of an input signal. An outputis present at the reset output terminal following said predeterminedperiod of time after an input signal is applied to the delay fiop. Incertain delay flops, the predetermined period of time is adjustable. Forexample, in FIG. 3a, a relay timing circuitry is provided for varyingthe timing of the delay fiop DF4 among the intervals 20 ms, 600 ms. and633 ms. In practice, the predetermined periods of time are adjusted byapplying appropriate voltages or connecting appropriate resistors to therecovery circuit of the delay flop. A resettable delay flop RDFcontinues to provide an output whenever the frequency of the inputsignal exceeds a fixed value.

The clear thyrafiop may be a circuit such as the thyraflop shown in FIG.7 of US. Patent No. 2,860,756.

The broad erase head is a conventional erase head which precedes theread-write heads and operates to erase coded signals on all eightchannels.

Referring to FIG. 4b, there is illustrated a record-verify relay (RVRLY) having one terminal of its coil coupled to a point of referencepotential, such as ground, and its other terminal adapted to receive anenergizing potential through either one of two paths. In one path is themanually operated function selector record switch (FSR-3); in the otherpath is the fifth pole (COL5), normally open. of the change-one-linerelay. When the apparatus is in the record cycle, the selector switchFSR3 is closed, energizing the RV relay, thereby switching all the RVrelay poles to their R position. During the verify cycle, the selcctorswitch FSR-3 is open so that the RV relay is deenergized and the RVrelay poles are in their V position. As will later be described, duringa change-oneline operation the relay pole COL-5 is closed.

Referring to FIG. 40, there is illustrated a write-read relay (WR RLY)having one terminal of its coil connected to the normally open contact Rof a record-verify relay pole RV7. The other terminal of the write-readrelay WR RLY is connected to a power source through normally closedrelay contacts of poles REV-1, COLB-9, and CR9. The write-read relay isdeenergized whenever the verifier is in the verify condition, exceptduring the change-one-line operation for the period when the poleCOL-B-9 is closed. In addition, the writeread relay is deenergizedwhenever the reverse relay pole REV1 is open, which occurs when the tapeis moving backwards, or during a carriage return operation when the poleCR-9 is open. When the write-read relay is energized, the head isconnected for writing on tape and erase current is flowing. When thewrite-read relay is deenergized, the head is connected for reading fromtape.

As shown in FIG. 4a, the left margin relay is actuated when the carriageis in the left margin position, at which time the left margin switch isautomatically closed by the typewriter carriage mechanism byconventional means not shown. The pole CR-9 must be closed in order forthe left margin relay to be energized.

Referring to FIG. 4c, the ribbon change actuator is connected at oneterminal of its coil to a power source and connected at its otherterminal to a normally closed contact V of a record-verify pole RV-8which has its arm connected to a point of reference potential, such asground. When a circuit is completed through the ribbon change actuator,the typewriter is adapted to print in red ink. When the ribbon changeactuator is deenergized, the typewriter is adapted to print in blackink.

Referring to FIG. 4e, a reverse relay pole REC-11 has its arm connectedto a source of energizing potential. The normally closed contact of thepole REC-11 and the normally open contact of the pole REV-11 areconnected, respectively, to the forward and backward terminals of acapstan motor, so that, when the reverse relay REV-11 is energized, themotor turns in reverse direction.

Before continuing with a description of the various figures, thefollowing background is given to achieve a better understanding of thisinvention.

During the verify function, various keys are operable in accordance withthe following conditions:

(I) The carriage return (CR) key on the typewriter is operable at anytime, except after a greater than error or a less than 120" error hasbeen detected.

(2) The backspace (BS) key is inoperable, except after a comparatorerror has been detected.

(3) The trip key is operable only at the 120 position with no error.

(4) The change-one-line (COL) key is operable only in the left marginwith no error.

(5) The 120 correct key (CRT) is operable at all times.

(6) The fill key is operable whenever the keyboard is unlocked.

The keyboard is operable, except during the following operations: load,change reels, rewind, backspace, carriage return, 120 correct, fill,trip, when error relay is energized, when display switch is transferred,when reverse relays are energized, for short interval after the reverserelay transfers back to the deenergized state, and when a special errorrelay is energized.

FIGS. 3a, 3b, and 3c illustrate various time periods involved inconnection with several components of the embodiment of this invention.In addition, FIGS. 2a and 2b also illustrate various time periods ofcomponents used in this invention. These values are determined by takingin consideration the velocity of the tape at full speed, the timerequired to attain full speed after actuation of the clutch by theflip-flop FF-l, the flux build-up time for the clutch, and the timerequired for acceleration. In addition, various times are required toreach a full stop after restoring the flip-flop FF-l, for flux builduptime for the brake, and the time required for deceleration.

RECORD OPERATION In the record cycle, the verifier records informationon tape. There are five record functions: normal type, fill, trip,backspace, and carriage return. The functions of flip-flop FF-l and thedelay fiops shown in FIGS. 2a and 2b in the record operation aresummarized below in open contacts, now closed, of write-read relaypoles, through appropriate encoding switches, to read-write Table 1.heads corresponding to the closed encoding switches,

TABLE l.-EFFE(7TS F FLIP-FLOP 1 AND I)TLTU\IV*FLL)P OUTPUTS IN RECORDOPERATION Flip-Flop Normal Type Fill Trip Backspace Carriage Return Sit7777777777 THIN? forward Tape fUTWtll(l Tape forvmrrL Tape rcvg ge VTflpg rgvisrs Restored .1 Tape stop Tape stop Tupi; stop. Ta e Sto ,7 Tm Dl l.

g 7 i 7 V 7 7 H 4157 d h n, 4.67 ms. delay Not Set 1137 ms. delay.77777777 1.67 ms. dela Recovered Set lll l Set 1 1*! Set DI n gm, pug DF Z:

Set 7777777777 Write urrent flows"... Write current flows L 7 N0 m m 7 7v V i V v 7 H 2 ms delay. D Recovered"...v Restore 1 1--11... Restore FFl... I. Rostum 1T4 m Restore 1fp e W N set H Nut sct.... H 350 ms. dcla3501115. (I lay 350 mg (Mm.- Rwuvumq 7 g g 7 7 7 Set lll t and FF l SetI F-I Set IF-l. DF

g t I, "313E115. delay Not set Not set, Recovered litSlOl't. FF I. "N"DF 5:

slt-kdveenne Not set. Recovered DFAi:

Set, Recovered st Recovered a I No etleci. in record operation.

Normal type In the record phase, the function selector swtieh is closed,closing FSR-3 (FIG. 4b) and energizing the RV relay. This reverses thesetting of the RV relay poles from their shown positions.

The operator depresses a character key. Normal typewriter action takesplace, printing the character and stepping the carriage. In addition,encoding switches appropriate to that character are closed, and a printaction switch is transferred. The mechanism for actuating the encodingswitches and the print action switch is not shown herein since it doesnot form part of this invention and may be conventional. This printaction switch is operated each time a character key on the typewriter isactuatcd. This switch stays closed for about ms.

Referring to FIG. 2b, the actuation of the print action switch PAScauses a voltage potential to be passed, via a normally closed rightmargin switch SW2. to the normally open contact R, now closed, of arecord-verify pole RV- 5. The potential passes through its arm, and abuffer, to the normally open contact R, now closed, of a recordverifypole RV9, passing through its arm to a normally closed error pole ERR6which is connected to set a clutch flip-flop FF-l. The flip-flop FF-l,when set, operates a tape center drive capstan clutch, thereby drivingthe tape.

Referring to FIG. 4e, it is noted that the capstan motor is in itsforward condition due to the reverse relay being deenergized. Therefore,when the print action switch PAS is operated, tape moves forward.

The voltage pulse generated from the print action switch PAS, whenactuated, is further connected via a line 116 to set the delay flop DF5(FIG. 2a). The dclay flop DF5, when set, provides an output level on itsset output line, having a duration of four milliseconds (4 ms.). At theend of 4 ms., the output level on the set output line ceases; an outputlevel, instead, occurs on the reset (or recovery) output line. It isnoted that the recovery output of the delay flop DF-S has no effect inthe record function. The set output level of delay flop DF-S is coupledto the arm of a record-verify pole RV-l3. The normally openrecord-verify contact of the pole RV13, now closed, couples the level toset a delay flop Di l having a duration of 4.67 ms. The reset output ofthe delay flop DF-1 is connected to set the write delay flop DF2. Theset output of the delay flop DF2 energizes a write current generator, orwrite amplifier. Current therefrom is passed through the normally asshown in FIG. 5. The write-read relay WR is energized in the recordcycle by the RV-7 pole, as shown in FIG. 4a. The print action switch PASthereby, subsequent to starting of the tape, actuates the read-writeheads to record the proper electrical character representation onto thetape corresponding to the depressed character key.

Two milliseconds alter the write delay flop DF-2 was set, it resets(restores). An output from the reset terminal of the delay flop DF-2 iscoupled via the line 113 to the reset terminal R of the clutch flip-flopFF1 (FIG. 2b), which causes the flip-flop FF-l to reset, therebyproviding an output at its reset output terminal to actuate the brake,stopping the tape.

The delay time of the delay fiop DF-l is set at 4.67 ms. (as shown inFIG. 3b) to permit the tape to reach full operating speed before thewrite current is applied to the read-write heads, and to give properspacing between characters on the tape. The delay time of the delay flopDF-2 is set at 2 ms. to permit write current to flow a sufficient timeto record one character.

This procedure is repeated for each character of a blockette. When thecarriage moves from the 119 to the 120 position, the right margin switchSW-2 transfers automatically by the action of the typewriter carriage,thereby removing the supply voltage from the print action switch PAS andenergizing the right margin relay RM RLY, as shown in FIG. 213.

The purpose of a fill operation is to quickly fill in a blockette orpart of a blockette with a no information code, such as zero or space.The mechanical positioning of the carriage is accomplished by the tabmechanism of the typewriter. The operator presets the desired tab stopsand selects the type of fill desired (either Zero or space).

The tab fill switch is ganged to the fill key on the typewriter so thatdepression of the fill key releases both the carriage which moves towardthe first tab stop, and transfers the tab fill switch, TAB FILL SW-1.Referring to FIG. 2c, the actuation of the switch TAB FILL SW-l actuatesthe TAB RELAY and, in addition, energizes the KEYBOARD LOCK ACTUATOR.The TAB RELAY, when actuated, causes its associated tab poles to beenergized and to be placed in their opposite conditions to those shownin the drawings. Note, that all relay poles and switches are shown inthe drawings in their deenergized or normal positions, for simplicity ofillustration.

As shown in FIG. 20, the actuation of the TAB-1 relay pole deenergizesthe KEYYBOARD UNLOCK ACTU- ATOR; the closed switch TAB FILL SW-lenergizes the KEYBOARD LOCK ACTUATOR, locking the keyboard. The polesTAB2 and TAB-6 (shown in FIG. 2b), when energized, have no effect in therecord function.

Referring to the upper right-hand corner of FIG. 2a, the pole TAB-8,when energized, completes a circuit to energize the backspace lockactuator BS LOCK ACT through the normally closed contact of the poleERR-7, thereby locking the backspace key. In addition, a circuit iscompleted from the power source through the carriage return lockactuator CR LOCK ACT, through the now closed contact of the pole TAB-8to ground, thereby locking the CR key. The pole TAB-9 (FIG. whenenergized, disconnects the write current generator from the encodingswitches and connects the write current generator to the proper channelsfor fill (7 and 8 for space, 1, 6, 7, and 8 for zero).

A tab commutator is ganged to the typewriter carriage and is driventhereby, and as the carriage moves from the zero (i.e., left margin) tothe one position, the tab commutator (FIG. 2b) generates a pulse. Thispulse travels through the now closed contact of the pole TAB-5, throughthe now closed contact of the pole RV-14, and hence to the line 116 andto the now closed contact of the pole RV-S. The pulse passes through thepole RV5, through the now closed contact of the pole RV9, and thenormally closed contact of the pole ERR-6 to set the clutch flip-flopFF-l. The tape moves forward.

The pulse generated by the tab commutator on the line 116 is connectedto set the delay flop DF-S, as shown in FIG. 2a. The set output of thedelay flop DF-S, which output lasts for a period of 4 ms., is connectedthrough the now closed contact RV-13 to set the delay flop DF-l. Thereset output of the delay flop DF-S has no effect in the recordoperation. The reset output of the delay flop DF-l, which output occurs4.67 ms. after the delay flop DF1 is set, is connected to set the writedelay flop DF-2. The set output of the delay fiop DF-Z has a timeduration of 2 ms., the time desired to record one zero or one space onthe tape, which output is connected to the write amplifier (FIG. 2a).The write current then flows through the now reversed TAB9 pole to theappropriate heads to record either a zero or a space, as shown in FIG.5. The reset output of the delay flop DF2, upon resetting, is connectedvia the line 113 to reset (restore) the clutch flip-flop FF1, therebystopping the tape.

A short time after the flip-flop FF1 is restored, another pulse isgenerated by the tab commutator. The above cycle of operation isrepeated for each commutator sequence or carriage position of the fill.A governor, not shown, limits the speed of the carriage to permitsufiicient time for a cycle to be completed for each character of thefill. The length of the fill is determined by the position of the tabstops.

When the carriage enters the position of the last character of the fill,a tab blade is actuated to stop the carriage and force an end-ofltabpush rod (not shown) to operate an end-of-tab switch END TAB SW-l, shownin FIG. 4d. The actuation of the switch END TAB SW1 deenergizes the tablock actuator by providing an open circuit therethrough. When the tablock actuator is deenergized, all the associated tab poles return tonormal, thereby completing the fill operation. The pole TAB6 revertsback to the position shown in FIG. 4d, thereby keeping the tab lockactuator in a deenergized condition until a subsequent fill operation.The operator can perform an additional fill operation or continue torecord by typing.

A skip fill operation is identical to a fill operation except that alltab stops are by-passed; the fill operation continues to the 120position.

Trip

After a blockette has been recorded, the operator can advance the tapeand return the carriage to the zero position. This procedure is termed atrip operation. The trip key is locked at all times except when thecarriage is in the 120th position. When the carriage moves from the119th to the 120th position, the right margin switch SW-Z (FIG. 2b),which may be ganged to the typewriter carriage automatically, transfersand energizes the RM relay.

Referring to FIG. 4], there is shown the normally open contact of thepole RM-4 connected through the normally closed contact of the pole ERR3which is connected to the tri unlock actuator. Upon actuation of theright margin relay, the pole RM-4 closes, completing a circuit from apower source through the poles RM-4 and ERR3 to energize the trip unlockactuator. The energization of the trip unlock actuator unlocks the tripkey to permit actuation thereof by an operator. It is noted, therefore,that the trip key is free for operation only when the carriage is at theright margin when no error is detected.

Referring to FlG. 2c, the actuation of the pole RM7 deenergizes thekeyboard unlock actuator and energizes the keyboard lock actuator,locking the keyboard so as to prohibit the actuation of keysaccidentally during a trip operation.

The actuation of the relay pole RM-3 connects the normally open contactof the trip switch TRIP SW to the trip relay, as shown in FIG. 211. Asource of positive potential is connected through a normaliy closedcontact of the pole TAB-6, through the normally closed contact of thetrip switch TRiP SW whose arm is connected to one side of a capacitor.The other side of the capacitor is connected through a normally closedcontact of a pole ERR1 which arm is connected to ground.

When the operator depresses the trip key, a trip symbol, such as anunderscore is printed. A trip lift arm (not shown) transfer the tripswitch TRIP SW. The trip switch discharges the capacitor through the nowclosed contact of the pole RM-3 to energize the trip relay.

The energization of the trip relay actuates the pole TRIP5 to provide aholding circuit for the relay from a source of potential through thepoles CR-9, TRIP-5, and SE1, and through the trip relay to ground. Theactuation of the pole TRIP-1 (FIG. 20) deenergizes the keyboard unlockactuator, thereby keeping the keyboard locked during the trip operation.The pole TRIP4 (FIG. 20) connects the set output of the clutch flip-fi0pFF1 via the line to the set input terminal of the trip delay flop DF-4.The pole TRIP8 (FIG. 2b), when energized, connects the trip relay to therelay reset thyratron via normally closed contacts of the poles COL-2and SE-7. The pole TRIP-9, open when energized, provides an open circuitbetween the carriage return switch CR SW-l and the carriage return relayCR RLY. The poles TRIP-3, TRIP6, and TRIP-7 have no effect in the recordoperation.

It is noted that the carriage return relay CR RLY functions to energizethe various CR relay poles. The operation of the carriage returnactuator CR ACT. functions to mechanically return the carriage to thezero position.

The TRIP-2 pole is illustrated in both FIG. 2a and FIG. 2b, forsimplicity of illustration. When the pole TRIP-2 is not actuated, acircuit is completed from a power source, to the normally closed contactof the pole TRIP-2, through its arm, to one terminal of a capacitor; theother terminal of the capacitor is connected to ground. Both the relaypole TRIP-2 and the condenser associated therewith are common to thecircuitry shown in FIG. 2a and FIG. 2!). Upon actuation of the poleTRIP-2, as shown in FIG. 2b, a circuit is completed which discharges theTRIP2 capacitor through the now closed (normally open) TRIP-2 contact toenergize the carriage return actuator CR ACT, returning the carriage tothe zero position. In addition, as the pole TRIP2 is actuated, as shownin FIG. 2a, the capacitor discharges to set the bounce delay flop DF-3which has a 350 ms. time period. The reset output of the bounce delayflop DF-3 is coupled to set the clutch flip-flop FF-l, via the line 115,through the poles RV-9 and ERR6. The set output of the flip-flop FF1energizes the clutch to drive the tape forward. In addition, the setoutput of the flip-flop Fl1 is connected via the line 110 and the nowclosed contact of the pole TRIP-4 to set the trip delay flop DF-4. Theset output of the trip delay flop DF-4 is coupled via the line 115,through the poles RV-9 and ERR-6, to apply an energizing signal to theset input of the flip-flop FF1, holding the clutch flip-flop FF-l in itsset condition.

After 633 ms., which is the time period (as shown in FIG. 3a) of thetrip delay flop DF-4, during which time the tape is advanced 1.9 inches,the delay flop DF-4 recovers. The reset output of the delay flop DF-4resets the clutch flip-flop FF1, via the record contact of the pole RV19and the line 113, stopping the tape. The reset output of the flip-flopFF-l (FIG. 2b), being connected to the grid of the relay resetthyratron, fires the thyratron. The relay reset thyratron, upon beingfired, deenergizes the trip relay via the poles COL2, SE-7, and TRIP-8by effectively shorting the voltage supplied to the relay to groundthrough a suitable resistance, not shown. When the trip relay polesreturn to normal, the keyboard unlocks to permit the operator to recordthe next blockette.

Backspace Referring to FIG. 2a, the backspace lock actuator BS LOCK ACTis deenergized during a record operation except during a carriagereturn, fill operation, or reverse operation, as evidenced by the opencircuit switch and relays CR SW3, TAB-8, and REV-12 connected inparallel to the backspace lock actuator BS LOCK ACT to complete acircuit to ground.

When the operator depresses the backspace key, a backspace power armmoves the carriage back one space and closes the backspace switchBACKSPACE SW-l. Referring to FIG. 2a, the actuation of the switch BACK-SPACE SW-l energizes the keyboard lock actuator to prevent erroneousstriking of other keys. The closing of the switch BACKSPACE SW-1completes a circuit which energizes the reverse relay REV RELAY throughthe normally closed contact of the pole LM-l. The pole LM-l is actuated(open-circuited) when the carriage is in the zero position or leftmargin. Therefore, when the carriage is in the zero position, the tapeis prevented from moving backwards.

The energization of the reverse relay actuates its respective poles tofunction as follows: the pole REV-11, shown in FIG. 4e, causes thecapstan motor to reverse for reverse tape travel. The pole REV-12, shownin the upper right-hand corner of FIG. 2a, completes a circuit toenergize the backspace lock actuator BS LOCK ACT. In addition, as shownnear the center of FIG. 2a, the pole REV-12 (duplicated for simplicityof description) deenergizes the broad erase head through the functionswitch FSR-S. The voltage level at the capacitor associated with thepole REV12 increases, transmitting a pulse through the capacitor to setthe bounce delay flop DF-3. The pole REV1, shown in FIG. 4a,open-circuits to deenergize the write-read relay WR RLY. Thedeenergization of the relay WR RLY causes its associated poles toachieve the read position.

Referring to FIG. 3b, the actuation of the relay pole REV-8 causes thedelay time of the delay flop DF-l to be 1.67 ms.

The actuation of the relay pole REV-9 (FIG. 3c) which causes theinterval of the resettable delay flop RDF to be 30 ms., and theactuation of the relay pole REV-6 (FIG. 2b), have no effect upon thebackspace operation during the record function.

As shown in FIG. 2b, the anode of the relay reset thyratron is connectedthrough the normally closed contact of the relay pole TRIP-8, throughthe now closed relay pole REV3, to line 200 which connects to thereverse relay REV RELAY shown in FIG. 20. As shown in FIG. 20, the relaypole REV-2 supplies holding current to the reverse relay REV RELAY. (Therelay pole REV-2 shown in FIG. 2a which is coupled to the error relaythrough the pole SE-9, and which is coupled to the delay flop DF-3 byvarious other poles, has no effect upon a backspace operation during arecord function.)

The pole REV-14 (FIG. 2a), when actuated, removes current supplied tothe clear thyraflop and the delay flop DF-6 via line 112 (FIG. 2b). Therelay pole REV-7 (FIGS. 2a and 5) connects the read-write heads to theresettable delay flop RDF through the normally closed pole TRIP-6. Theenergization of the relay pole REV-S (FIG. 2c) causes an equal potentialto be present at both terminals of the keyboard unlock actuator, therebydeenergizing the keyboard unlock actuator; the keyboard lock actuator isenergized by the now closed relay pole REV-2.

Referring to the center of FIG. 2a, the transfer of relay pole REV-l2sets the bounce delay flop DF-3. The reset output of the delay flopDF-3, which occurs 350 ms. after being set, is connected (via the line115, the now closed contact of the pole RV-9, and the relay pole ERR6)to set the clutch flip-flop FF-l. The flip-flop FF1, when set, energizesthe clutch. The capstan motor, FIG. 4e, is moving in the reversedirection; therefore, the tape moves in the reverse direction. The pulseof the previously recorded character is read by the readwrite heads(FIGS. 2a and 5). This pulse (which is amplified by suitable means) ispassed through the read contacts of the read-write poles and hencethrough the normally closed relay pole CR-6 to set the delay flop DF1.The reset output of the delay flop DF-l, which occurs 1.67 ms. afterbeing set, sets the write delay flop DF-Z. The reset output of the delayflop RF-2 is connected via the line 113 to reset the flip-flop FF1 whichcauses the tape to stop. The reset output of the flipflop FF-l, inaddition to actuating the brake which halts the tape, fires the relayreset thyratron by applying an enabling signal to its grid. The firedrelay reset thyratron provides a discharge path for deenergizing thereverse relay REV REYAY through the line 200, and relay poles REV-3 andTRIP8. All the reverse relay poles then return to normal, as illustratedin the drawings, thereby completing the backspace operation. In summary,by depressing the backspace key, the carriage moves back one space andthe tape positions so that when a new character is typed, the oldcharacter is erased.

Carriage return A carriage return operation returns the carriage to zeroposition (left margin), spaces the paper, and repositions the tape sothat the first character of the blockette is ahead of the read-writeheads so that when a new blockette is recorded, the old blockette(corresponding to the blockette operated upon prior depression of thecarriage return key) is erased.

To perform a carriage return operation, the operator depresses thecarriage return key. This operation can be performed with the carriageat any position. Depression of the key causes a power arm to engage amechanical carriage return clutch, which causes the carriage to returnto the zero position. The mechanical clutch also causes various CRswitches to be actuated. One of the CR switches, CR SW-3 (FIG. 2a),closes to energize the backspace lock actuator BS LOCK ACT and thecarriage return lock actuator CR LOCK ACT, thereby locking the backspaceand carriage return keys.

The switch CR SW1 (FIG. 2b) has a normally closed contact connected to apotential source. Its arm is connected to one terminal of a capacitorwhose other terminal is connected to a point of reference potential,such as ground. When the switch CR SW1 is in its deenergized position,the associated capacitor is charged by the potential source. Uponactuation of the CR SW-l, the capacitor discharges through the normallyopen contact of the switch so that the carriage return relay CR RLY isenergized via the normally closed contacts of the poles 120 A1, TRIP-9,and LM-3. It is noted that the relay CR RLY is prevented from beingenergized when the carriage is in zero position due to the relay poleLM-3 being open at that time.

The energization of the relay CR RLY causes the associated relay polesto operate as follows:

Referring to FIG. 3b, the relay pole CR-2, when actuated, causes thetime of the delay flop DF1 to be 1.67 ms. (during both the record andverify functions). The normally open contact (now closed) of the poleCR8 (FIG. 2c) connects a voltage source through its arm to a capacitorwhich is coupled to ground through the now closed contact of the poleRV8, thereby charging the capacitor. As shown in FIG. 2a, relay poleCR-4 connects the normally closed contact of the pole REV-2 through acapacitor to provide an input pulse to the set input of the delay flopDF-3. The relay pole CR-3, when energized, connects the reset output ofthe resettable delay flop RDF to the line 113 which is connected toreset the fiip-fiop FF-l. The relay pole CR--1, when energized,open-circuits to prevent the set output of the flip-flop FF1, via theline 110, from passing an input pulse therethrough and the pole TRIP-6,thereby preventing the setting of the resettable delay flop RDF. Therelay pole CR6, when energized, disconnects the output of the read-writeheads from the input of the delay fiop DF1. Note that there are twopaths in the circuit, pole CR-6 and pole REV-7. The relay pole (TR-5, asshown in FIG. 2b, connects the carriage return relay CR RLY t the relayreset thyratron via the normally closed contacts of the poles REV3 andTRIP- 8.

Referring to FIG. 4 1, the relay pole CR-9, when energized, removescurrent from the WR relay, thereby deenergizing same and placing therelay in its read condition. In addition, the relay pole CR-9, as shownin FIG. 22.1, when energized, provides a holding current for thecarriage return relay CR RLY.

As shown in FIG. Zr, the relay pole CR-7, when deenergized, connects apower potential to charge a capacitor. Upon the energization of thecarriage return relay, the pole CR-7 is actuated to discha ge thecapacitor, causing the reverse relay REV RELAY to be energized.

The energization of the reverse relay actuates the as sociated reverserelay poles.

Referring to FIG. 4e, pole REV-11, when deenergized, connects apotential source to drive the capstan motor in a forward direction. Uponenergization of the REV RELAY, the pole REV-11 is actuated, removing theenergizing potential from the forward windings of the capstan motor andplacing an energizing potential to the backward winding to drive thecapstan motor in the reverse direction.

Referring to FIG. 2a, the pole REV-12 has its arm connected to groundand its normally closed contact connected through a resistor to a pointof positive potential. A capacitor couples the normally closed contactof the pole REV12, through a butter, to the set input of the bouncedelay flop DF-S which has a period of 350 ms. The output of the delayflop DF-3 is coupled. via the line 115, through the record contact ofpole RV-9 and through the pole ERR-6 to set the clutch flip-flop FF-l.

The pole REV-14 has no function in the record operation. Its purpose isdescribed hereinafter in connection with the verify description.

Referring to FIG. 4a, the relay pole REV-1, when energized, deenergizcsthe write-read relay WR RLY, The relay pole REV-2, as shown in FIG. 2c,is used as a holding contact to keep the REV RELAY energized.

The REV RELAY is connected via the line 200 through the pole REV-3, nowenergized, and hence through the pole TRIP8 to the anode of the relayreset thyratron.

As shown in FIG. 20, the pole REV-5, when energized, applies a potentialto dcenergize the keyboard unlock actuator. The relay pole REV-6described hereinafter with the verify function has no utility inconnection with the record function.

The relay pole REV-7, upon being energized, switches the output of theread-write head amplifier from the delay flop DF1 and, therefore,connects the head amplifier to the input of the resettable delay flopRDF via the pole TRIP6.

As shown in FIG. 3b, the actuation of the pole REV-8 causes the time ofthe delay flop DF-l to be 1.67 ms.

As shown in FIG. 30, the actuation of the pole REV-9 causes the time ofthe resettable delay flop RDF to be 3!] ms.

In operation, the encrgization of the pole REV-12 causes a pulse to beapplied to the delay flop DF-3. The reset output pulse occurring 350 ms.later from the delay flop DF-3 is connected via the line 115, pole RV9,and pole ERR6 to set the clutch flip-flop FF1. The tape thereby moves inreverse direction. As the tape moves in the reverse direction, therecorded characters are read by the rend-write heads and transmitted inthe form of pulses through the poles REV7 and TRIP-6 to set theresettahle delay flop RDF. The characters read by the heads from thetape produce pulses which come at such frequent intervals that theresettable delay flop RDF does not reset until 20 ms. after the pulse ofthe first character of the blockette has passed the head. The blocketteis now 30 ms. (0.090 inch) to the left of the heads.

The reset output of the resettable delay flop RDF is coupled through thepole CR-3 (now energized) and line 113 to reset the clutch fiip-flopFF1. thereby stopping the tape. The reset output of the flip-flop FF-l,in addition to stopping the tape, applies an enabling signal to fire therelay rcset thyratron. The relay reset thyratron decncrgizes the REVRELAY through the poles TRIP-8 and REV3.

It is noted that the CR relay remains energized because it is connectedto the relay reset thyratron through the normally closed side of thepole REV3. All the reverse relay poles transfer back to normal. Therelay pole REV-11 causes the capstan motor to rotate in a forwarddirection. The pole REV-2, upon assuming its normal condition, causes apulse to be generated by means of its connected capacitor via the poleCR-4 to set the delay flop DF-3. The reset output of the delay flop DF-3sets the clutch flip-flop FF-l causing the tape to move forward. Thefirst character read by the read-write heads generates a pulse throughthe pole REV-7 to set the delay flop I)F-1. The reset output of thedelay fiop DF-l sets the delay flop DF-Z. The reset output of the delayflop DF-Z, via the line 113, resets the flipdlop FF-l, stopping thetape. The reset output of the flip-flop FF1 fires the relay resetthyratron, thereby deenergizing the CR relay via the poles TRIP-8, REV3,and CR5. Assuming that the forward direction of the tape is from rightto left, the first character of the blockette is now one characterposition to the right of the read-write heads.

During the time the CR relay has been energized, the pole CR-8 (FIG. 20)was charging a capacitor via the pole RV-S. When the pole CR-S returnsto normal, it discharges the capacitor to cause the reverse relays to beenergized, thereby causing all reverse poles to again transfer. Thecapstan mot-or is reversed. The pole REV12, when actuated, causes apulse to be transmitted to set the delay flop DF3. The reset output ofthe delay flop DF-3 sets the clutch flip-flop FF-l, via the line 115 andpoles RV-9 and ERR-6, causing the tape to move in reverse.

The first character read by the heads generates a pulse via the pole CR6to set the delay flop DF-l, causing the following to occur: the resetoutput of the delay flop DF-l sets the delay flop DF-Z; the reset outputof the delay flop DF-Z, via the line 113, resets the flip-flop FF1,stopping the tape. The reset output of the flip-flop FF-l, in additionto stopping the tape, fires the relay reset thyratron, therebydeenergizing the reverse relays, causing all the reverse poles to returnagain to normal. The pole REV-11 reverses the capstan motor for forwardtape motion. It is noted that the pole REV-2 does not set the delay flopDF3 because the poles CR-4, RV-l, SE3, and COL-B3 are open.

The tape is now positioned so that the first character of the blocketteis to the left of the heads. When the new blockette is recorded, the oldinformation is erased.

VERIFY FUNCTION The verifier, when in the verify function, comparesinformation from a source document with information previously recordedon tape. It also detects and corrects errors on the tape. When a key isdepressed, a character is typed in red, the carriage is spaced, and thetape is advanced one character. As long as the character typed and thecharacter on the tape are identical, the operator is free to continue totype at a normal rate wherein the tape continues to be verified. If thecharacters are not identical, either because of an operator error or amachine error, the keyboard locks and a light on the display panel (notshown) indicates the type of error that occurs. Various interlocks areprovided to prevent the operator from performing any operation otherthan the one necessary to correct the particular type of error made.

Normal verify The record-verify relay RV, as shown in FIG. 4b, isenergized only when the verifier is in the record function (when theswitch FSR3 is closed) or when the verifier is in the changeone-lineoperation (when the pole COL-5 is actuated) during the verify function.For a normal verify the RV relay is deenergized; the RV poles are intheir deenergized or V condition.

Referring to FIG. 2a, current flows from a positive potential sourcethrough the pole REV-2, normally closed, through a resistor connected toground. Connected to the pole REV2 is a capacitor which is connected toground through another registor. Prior to the RV relay being deenergizeda charge is built up on the capacitor. Upon deenergization of the RVrelay, a pulse is transmitted from the capacitor through the now closedcontact of the pole RV-l to the delay flop DF-3 setting the delay flopDF3 which upon restoring transmits a signal, via the line 115, delayflop DF6, now closed pole RV-9, and pole ERR6, to set the clutchflip-flop FF-l, thereby driving the tape. The tape moves forward atnormal operating speed of three inches per second. When the firstcharacter of the first blockette passes the head, a voltage is inducedin the head coils for each channel that has a pulse recorded therein.These pulses are amplified and applied to the grids of the memorythyratrons corresponding to the channels, firing the thyratrons. At thesame time that one or more of the memory thyratrons are fired, a pulseis generated to set the delay flop DF-l via the poles REV-7 and (IR-6.The recovery of the delay flop DF-l sets the delay fl-op DF-Z. Therecovery of the delay flop DF-Z restores the flip-flop FF-l, therebystopping the tape. The first character of the hlockette is now in thememory and the carriage is in zero position. At this condition, theoperator can now proceed to begin the verify operation.

The operator types from the original document used by the operator whooriginally recorded the tape. When the key operating the first characterof the source document is depressed, a power arm rotates a type-barbellcrank, forcing the type bar to the platen. The type-bar bellcrank iscoupled to an encoding lift arm (not shown) so that when the bellcrankis rotated, the associated lift arm is raised, thereby closing acombination of encoding switches corresponding to the code of the lettertyped. The switching code used is shown in the U.S. Patent 2,860,325 andherein shown by the table below.

When the encoding switches are closed, circuits to the comparator arecompleted, via the pole RV-3, as shown in FIG. 5. The lift arm alsotransfers the print action switch PAS (FIG. 2b) which sets the delayflop DF-S via the line 116.

The set output of the delay flop DF5 has no effect during the verifyfunction due to the open circuit provided by the deenergized pole RV-13.

The recovery of the delay flop DF-S (that is, when it resets) causes apulse to be generated to the probe input of the comparator (see FIGS.20, 5), and also to the delay flop DF7. The setting of the delay flopDF-7 alerts the error thyratron until the delay fiop DF7 resets two andone-half to three milliseconds later. If the comparison is positive,that is, a memory thyratron fired for each encoding switch closed, thereis no output from the comparator and thus no error. If the comparison isnegative, upon being probed, the comparator produces an output, therebyfiring the error thyratron.

TABLE 2 Pulse Code Character Iulsc Code Character 1 A O i] ll 1 0 C l 1l) 0 1 E l 0 F l U G i 0 l IT 1 0 I 1 1 J O 0 K 0 001000.. 5 0 L 1001001 (i I \l l t 'i 1 N (l s U 0 1 9 U l 1 Period 1 Q, 1 Comma 0 R t]Semi-colon 1 S (l llyphcn l T 0 Percentage 0 U 0 Slash (f) Afterapproximately 35 ms., the print action switch PAS (FIG. 2b) returns tothe normal position. The return of the print action switch PAS clearsthe memory and sets the delay flop DF-6 via the line 111, normallyclosed right margin switch SW1, the pole REV-14, and line 112. The resetoutput of the delay flop DF-G, six milliseconds later, sets the fiipflopFF1 via the poles RV-9 and ERR-6. The tape moves forward to read thenext character.

The second character on the tape is read by the readwrite heads, and viathe read-write relay poles 1-8 (FIG. 5), fires the appropriate memorythyratrons and generates a pulse to the delay flop DF1 (FIG. 2a) via thepoles (IR-6 and REV-7. The reset output of the delay flop DF-l sets thedelay flop DF2. The reset output of the delay liop DF-Z resets theflip-flop FF-l, thereby stopping the tape.

The second character is now in the memory and the operator can continueto verify by typing the second character, which closes the appropriateencoding switches and the print action switch PAS. Coded signals fromthe encoding switches (via the pole RV3) and from the memory arepresented to the comparator (FIG. 5). The print action switch PAS (FIG.2b) provides a pulse, via the line 116. to set the delay fiop DF-S (FIG.2a), which, upon restoring 4 ms. later, probes the comparator. Thecomparator, upon being probed, provides an output signal, in the eventof a non-identity, to one grid of the error thyratron. The reset outputof the delay flop DF-5 17 provides a delay pulse via delay flop DF-7 tothe second grid of the error thyratron. Upon energizing levels at bothgrids, the error thyratron fires, actuating the error relay (FIG. 2a)and locking the keyboard (FIG. 20).

18 the carriage is at the zero position, the tab stop is set at the 10carriage position. To perform a fill operation the operator depressesthe fill key. The tab blade moves up; the carriage is freed to move tothe 10 carriage position;

The print action switch, upon returning, causes the mem- 5 the tab fillswitch SW-l transfers (FIG. 20), thereby ory to clear, and starts thetape so that the third characenergizing the TAB relay and the keyboardlock actuator. ter can be read. The verify operation continues in thisThe various tab poles are transferred with the following manner untilthe carriage reaches the 119 position. At results: the pole TAB-1, asshown in FIG locks the position 119 the right margin switch SW-ltransfers. keyboard. The pole TAB-2, when energized, disables When theoperator types the 120 character, the carriage the 120 correct switch(FIG. 2b). The pole TAB-5 conmoves from the 119 to the 120 position.When the right nects the tab commutator (FIG. 2b) to the delay flopmargin switch 1 is transferred, is prevents the print action DF-6 viathe line 111, right margin switch SW-l, the switch from clearing thememory and setting the delay pole REV-l4, and the line 112. The poleTAB-6, flop DF-6. If the delay flop DF-ti is not set, it cannot shown inFIG. 4d, energizes and supplies holding current recover to set theflip-flop FF-l. Therefore, the tape to the tab lock actuator. Inaddition, as shown in FIG. does not move until a trip or carriage returnoperation is 2!), the pole TAB-6 removes the supply voltage from theperformed. The carriage is in the 120 position and the 120 CRCT, TRIP,and COL switches. The pole TAB-8, 120 character is in the memory. asshown in FIG. 2a, operates to lock the backspace and As the carriagemoves from 119 to 120 the right margin carriage return keys bycompleting circuits to their reswitch SW-2 transfers at 119%, energizingthe RM relay spective BS and CR lock actuators. The pole TAB-9 andremoving the supply voltage from the print action has no effect duringthe normal verify operation. It conswitch (FIG. 2b), causing thefollowing results: the pole nects the write circuits to zero or to spacefill circuits, RM-7 (FIG. 2c) transfers, deenergizing the keyboard whenenergized, and when deene-rgized, connects the unlock actuator andenergizing the keyboard lock actuwrite circuits to the encodingswitches. The only funcator to lock the keyboard. 5 tion of the poleTAB9 during the verify function oc- Referring to FIG. 4 when the poleRM-4 is closed, curs during a change-onedine operation. The pole TAB-actrcurt is completed via the pole ERR-3 which ener- 15 transfers andsets the delay fiop DF-S due to a 65 gizes the trip unlock actuator,thereby freeing the trip volt level present on the arm of the poleTAB-15. (A dekey. The pole RM-3 (FIG. 2b) is closed, thereby enlay fiopprovides an output at its set output terminal, when set, of +10 volts;when reset, of volts.)

TABLE 3.EF FECTS OF FLIP-FLOP AND DELAY-FLOP OUTPUTS IN VERIFY OPERATIONComponent Normal Fill Trip Carriage Return Back Space Change One LineFF-l:

Set Tape moves 1 Tape moves Tape moves 1 Tape moves Tape moves Tapemoves. Tape stops 2 Tape stops 2 Tape stops 2 Tape stops Tape stops Tapestops. 1.67 ms. delay 1.67 ms. delay 1.67 ms. delay 1.67 ms. delay 1.67ms. delay 4.67 ms. delay. 2 SetDF-Z Set DF-2 SctDF-2 SetDF-2 Set DF-2Set DF-2. Set 2 ms. delay Set DF5 Fire 120-error 2 ms. delay 2 ms. delayEnergize write thyratron, it current (2 ms). necessary. Recover RestoreFF-l Restore FF-l Restore FF-l Restore I F l Restore FF-l Restore FF-l.Used at end of fill: Set 350 ms. delay 350 ms. delay... 350 ms. delay350 ms. delay 350 ms. delay 350 ms. delay. Recover Set DF6 and Set 6 SetDF-6 (and Set DF-6 clear Set DF-6 clear Set FF-l. DFJJ" clear memory.DF4).4 memory. memory.

st Not set.

Recover Probe comparator Probe comparator;

and set DF-7. set clear-memory thyraflop.

Set 6 ms. delay 6 ms. delay 6 ms. delay 6 ms. delay Bypassed. D RecoverSet FF-l Set FF'I Set FF1 F Set Alerts error Alerts error Not set Notset.

thyratron. thyratron.

Recover Inhibits error Inhibits error thyratron. thyratron.

1 If error is detected, circuit opens. Tape cannot move. 2 It error isdetected, circuit is jammed.

I After 120 characters have been recorded, the operator depresses thetrip key and a normal record operation trip takes place, except that DF4delay is 600 1115., instead of 633 ms.

4 Provides for 120-error detection.

5 DF-3 set, for normal operation, only for initial character to heverified by decnerglzation of the pole RV-l.

abling the trip relay. The operator can now perform a trip operation.The table below shows the effects of the flip-flop and delay-flopoutputs in the verify operation.

Fill

The set output of the delay flop DF-S does not set the delay flop DF-lbecause the pole RV-3 connecting the two delay flops is open-circuited,or in the deenergized condition. The recovery or reset output of DF-S,which occurs 4 ms. after being set, probes the comparator, checking thefirst character for odd or even parity. When an odd combination ofmemory thyratrons is fired, the comparator produces an output and firesthe error thynatron. When an even combination of memory thyratrons isfired, there is no output from the comparator and hence no error.

The tab commutator produces a pulse which sets the delay flop DF-6 andclears the memory, via the pole TAB-5, the line 111, right margin switchSW-l, the pole REV-14, and the line 112. The recovery of the delay 19flop DF-6, 6 ms. later, sets the flip-flop FF-l via the poles RV-9 andERR6, causing the -tape to move forward.

The second character is read by the magnetic heads into the memory (byfiring of memory thyratrons). The magnetic heads generate a pulsethrough the poles REV-'7 and CR6 to set the delay flop DF-l. Therecovery output of the delay fiop DF-l sets the delay flop DF-Z. The setoutput of the delay flop DF-2 sets the delay flop DF- via the poleTAB15. The restore output of the delay fiop DF-Z resets the flip-flopFF-l, thereby stopping the tape. The set output of the delay flop DF5has no effect due to the pole RV-13 being open, however, the recoveryoutput of the delay flop DF-S, 4 ms. after being set, probes thecomparator and sets the delay flop DF-7 which alerts the errorthyratron, checking the second character for proper parity.

Subsequently, the second commutator pulse sets the delay flop DF-6 andclears the memory thyratrons. The recovery of the delay fiop DF-6 setsthe fiip-fi-op FF1; the tape moves forward until the third character isread into the memory. The process of clear memory, start tape, read,stop tape, and probe comparator continues until the carriage reaches theninth position. The carriage moves from the ninth to the tenth positionwith the following results:

(1) The tenth commutator pulse sets the delay flop DF-6 and clears thememory. The recovery of the delay flop DF-6 sets the flip-flop FF-l. Theeleventh character is read into the memory, generating a pulse to setthe delay flop DF-l. The recovery output of the delay flop DF-l sets thedelay fiop DF-2 which recovery output is coupled via the line 113 toreset the clutch flip-flop FF-I, thereby stopping the tape. The setoutput of the delay fiop DF-Z, via the now closed pole TAB-15, sets thedelay flop DF-S which recovery output probes the comparator.

(2) The carriage comes to rest in the tenth position. The tab blade isactuated by the tab stop against a push rod, not shown, to open the ENDTAB SW-l, shown in FIG. 4d. The END TAB SW-l deenergizes the tab lockactuator after a 120 ms. delay.

The fill operation is completed. The carriage is in the tenth positionand the eleventh character is in the memory. The operator can nowperform another fill operation or continue to verify by typing on thekeyboard. It is noted that the carriage is limited to approximately 50characters per second or 20 ms. per character. This provides sufficienttime for the cycle of read, stop tape, probe, and start tape to takeplace between commutator pulses.

When the carriage moves to the 119 position, the right margin switchSW-l transfers, preventing the 120 commutator pulse from setting thedelay flop DF-6 and clearing the memory. Therefore, the flip-fiop FF1 isnot set and the tape is not advanced at that time.

A skip fill operation is identical to a fill operation except that whenthe skip fill key is depressed, the skip fill actuator is energized. Theskip fill actuator prevents the tab blade from moving up. All preset tabstops are by-passed. When the carriage reaches the 114 carriageposition, the skip fill actuator release switch, not shown, deenergizesthe skip fill actuator, allowing the tab blade to move up. The 120 tabstop engages the tab blade and ends the skip fill operation in the samemanner as a normal fill. The carriage comes to rest in the 120 position.The right margin switch SW4 prevents the 120 commutator pulse fromsetting DF-6 to cause further tape movement. The right margin switchSW-2 (FIG. 2b) energizes the right margin relay, actuating the rightmargin poles. The pole RM-4 closes, and in the event of no error,actuates the trip unlock actuator (FIG. 4;); the pole RM-7 (FIG. 2c)transfers to actuate the keyboard lock actuator. The operator can nowperform a trip operation.

20 Trip The purpose of a trip operation is to return the carriage tozero, advance the tape to the next blockette, and search for erroneouspulses in the space between blockettes. To accomplish a trip, theoperator depresses the trip key. The power arm rotates the type-barbellcrank, printing an underscore on the hard copy. The trip lift arm israised, closing the trip switch. The trip switch, as shown in FIG. 2b,energizes the trip relay via the now closed contact of the pole RM-3,thereby actuating all the trip poles with the following results: thepole TRIP-1 (FIG. 20) removes the potential to the keyboard lockactuator (the keyboard remains mechanically locked until the keyboardunlock actuator is energized); the pole TRIP3 couples the anode of the120 error thyratron to the 120-A relay (FIG. 2a); the pole TRIP-4 (FIG.20) connects the set output of the flip-flop FF1 to the set input of thedelay flop DF-4; the pole TRIP5 supplies holding current to the triprelay (as shown in FIG. 2b) via the poles CR-9 and SE-l; the pole TRIP-6prevents the resettable delay flop from being set; the pole TRIP-7places an enabling signal on the gate G-l (FIG. 2a); the pole TRIP-8connects the trip relay to the relay reset thyratron via the poles COL-2and SE7; and the pole TRIP-9 (FIG. 2b) prevents the switch CR SW-1 fromenergizing the CR relay through the poles 120-A-1 and LM-3.

The pole TRIP-2 simultaneously pulses the CR actuator (FIG. 2b) toreturn the carriage to zero, and sets the delay flop DF-3 (FIG. 2a).

The recovery output of delay flop DF-3 sets the delay flop DF6 via theline and clears the memory. The recovery output of the delay fiop DF-6sets the flip-flop FF-l via the poles RV-9 and ERR-6. The set output ofthe fiip-fiop FF-l causes the tape to move forward, and also sets thedelay flop DF-4, via the pole TRIP-4, for a duration of 600 ms.

The tape continues to move forward until the first character of the nextblockette is read into the memory. The read character fires the memorythyratron and gen crates a pulse via the poles REV-7 and (ZR-6 whichsets the delay flop DF-l, setting the delay fiop DF-Z which, in turn,restores the flip-flop FF-l, thereby stopping the tape. The reset outputof the flip-flop FF-l fires the relay reset thyratron, deenergizing thetrip relay.

The carriage is now in the zero position (i.e., left margin). The firstcharacter of the next blockette is in the memory. This completes thetrip operation.

The set output of the delay flop DF-4 alerts the gate 6-1 for aninterval of 600 ms. If, during this interval, an erroneous pulse on thetape (occurring between blockettes) is read by the magnetic heads, thedelay flop DF-l would be set (via the poles REV-7 and (JR-6). Therestore output of the delay flop DF-1 then sets the delay flop DF2 whichset output fires the error thyratron, indicating a greater-than-12Oerror, as described in furthe detail hereinafter.

Carriage return A carriage return during the verify function operates inthe same manner as a carriage return during the record function with thefollowing exceptions: the pole REV-2 sets the delay flop DF-3 via thepole RV-l instead of via the pole CR-4. The restore output of the delayflop DF-3, via the line 115, sets the delay flop DF-6 and clears thememory; the restore output of the delay fiop DF-fi sets the flip-flopFF-l. In contrast, during the record function, the delay flop DF-3by-passes the delay flop DF-6 and sets the flip-flop FF-l directly.

At the end of carriage return, the carriage is in the zero position(i.e., left margin) and the first character of the blockette is in thememory.

Backspace A backspace operation can be initiated during the nor malverify function only when the error relay is energized. The pole ERR-7(FIG. 2a), when actuated, deenergizes the backspace lock actuator,freeing the backspace key. To perform a backspace operation, theoperator depresses the backspace key. A backspace power arm steps thecarriage back one character position and closes the backspace switch SW1(FIG. 2c). The backspace switch energizes the keyboard lock actuator andreverse relay. The pole REV-2 (FIG. 20!) transfers, thereby deenergizingthe error relay and deionizing the error thyratron. The reverse relayreceives a holding current via the pole REV-2 (FIG, 20). The poles ofthe reverse relay function as in the carriage return operation. Therecovery of the delay flop DF-3, set by the actuation of the pole REV12,sets the delay fiop DP6 via the line 115 and clears the memory. Therecovery of the delay flop DF-6 sets the flip-flop FI L The tape movesin reverse due to the actuation of the pole REV11, shown in FIG. 4e. Thepulse generated by the character read by the read-write head istransmitted via the pole CR-6 to set the delay fiop DF-l, and hencesetting the delay flop DF-Z. The recovery of the delay flop DF-2restores the flip-flop FF-l via the line 113, thereby stopping the tape.The restore output of the fiipflp FF-l fires the relay reset thyratronwhich deenergizes the reverse relay via the poles TRIP-8 and REV-3 andline 200. The capstan motor reverses (FIG. 4e) and travels in theforward direction to prepare for forward tape motion. The pole REV-2transfers to normal, thereby setting the delay tlo DF-3 via the poleRV-l. The recovery of the delay flop DF-3 clears the memory and sets thedelay fiop DF-6 which, in turn, sets the flip-flop FF-l, causing thetape to move forward. The erroneous character is read back into thememory, and a pulse is generated via the poles CR-G and REV7 to set thedelay fiop DF-l. The recovery of delay flop DF-l sets the delay flopDF-Z which restores the flip-flop FF-l, thereby stopping the tape.

The erroneous character is now in the memory, the carriag: is steppedback one position, and the error relay is deencrgized. The operator cannow perform a 120 cor rect operation or verify the character.

Change one line The purpose of the change-one-line operation is tochange a complete blockette of information. If a lessthan-l error hasbeen made, the change-one-line operation is the only way to correct thiserror.

A change-one-line operation places the verifier in record While oneblocketle is recorded. Upon a subsequent trip operation, the verifier isreturned to verify and an automatic carriage return takes place. Theoperator must then reverify the blockette just recorded. A change-oneline oreration can be performed whenever the carriage is in the leftmargin and the error relay is not energized.

To perform a change-one-line operation, the operator depresses the COLkey. The COL key actuates the COL switch (FIG. 2b) which energizes theCOL and COLB relays with the following results: the tape is firstreversed for 600 ms., moving tape across the broad erase head, erasingthe first 1.5 inches of the blockette in question. The tape is thenrepositioned in a forward direction for 600 ms., returning the tape tothe approximate original position and driving out the COL-B relay. Thebroad erase head is energized during the entire ehange-one-lineoperation until a trip operation is performed. The trip time after achange-one-line operation is 20 ms.

The pole COL-B-1 deenergizes the keyboard unlock actuator (FIG. 2c); thepole COL-7 energizes the keyboard lock actuator, through the pole LM1,locking the keyboard. In addition, the pole COL7 energizes the REVrelay. The pole COL-B2 (FIG. 2b) connects the COI.-B relay to the relayreset thyratron via the poles REV3 and TRIP-8; the pole COL-2 connectsthe COL relay to the relay reset thyratron via the pole SE7, and

the normally open contact of the pole TRIP-8 (now open). The pole COLB 4supplies holding current to the COL-B relay; the pole COL-4 suppliesholding current to the COL relay. The pole COL-5 energizes the RV relay(FIG. 4b), placing the RV poles in the record position. The pole COL-6changes the timing of the delay flop DF-4 from 633 ms. to either 600 ms.or 20 ms.; the pole COL-B6, when energized, causes the timing of thedelay flop DF-4 to be 600 ms., when deenergized, to be 20 ms. (see FIG.3a). The pole COL-B-3 connects the delay flop DF-3 to the capacitorassociated with the normally closed contact of the pole REV2. The poleCOL-B-S inhibits pulses read from the magnetic heads. The pole COLB7(FIG. 2a) connects the set output of the flip-flop FF-l, via the line110, to the input of the delay fiop DF4. The pole COL-B-S (FIG. 2a)locks the backspace and carriage return keys; the pole COL-B- 9 keepsthe read-write relay decnergized (FIG. 4a). The pole COL-8 causes acapacitor to be charged, so that, upon deactivation of the pole COL-8,the capacitor energizes the CR relay (FIG. 2b). The pole COL-9 actuatcsthe broad erase head (FIG. 2a) via the switch FSR- 5 and the pole120-A-9.

The reverse relay, being energized, causes the pole REV-11 to transfer,reversing the capstan motor, thereby preparing for reverse tape motion.The pole REV-12 sets the delay flop DF3. The recovery output of thedelay tiop DI -3, via the line 115, sets the flip-flop FF-l, via thepole RV9, thereby causing the tape to move in reverse. The set output ofthe flip-flop FF-l sets the delay flop DF4 via the pole COL-B-7. Thepulse generated by reading the first character is inhibited by means ofthe pole COL-B-S which effectively shorts the output of the heads toground. The recovery of the delay flop DF-4, which occurs 600 ms. afterbeing set, restores the flip-flop FF-l via the pole RV-19, therebystopping the tape. The restore output of the flip-flop FF-l fires therelay reset thyratron which deenergizes the REV relay via the polesTRIP-8 and REV3 and the line 200. It is noted that the COL relay remainsenergized because the COL relay coil is connected to the relay resetthyratron via the normally open contact of the pole TRIP-8.

The reverse poles are transferred to their normal position. The poleREV-11 transfers to reverse the capstan motor to prepare for forwardtape motion. The pole REV-2 sets the delay flop DF-3 via the poleCOL-B3. The recovery of the delay flop DF3 sets the flip-flop FF- 1 viathe line and the pole RV9. The set output of the flip-flop FI I sets thedelay fiop DF-4 via the pole COL B-7. The recovery of the delay flopDF-4, 600 ms. later, restores the flip-flop FF-1 via the pole RV-19 andthe line 113 to stop the tape. The restore output of the flip-flop FF-lfires the relay reset thyatron. The relay reset thyratron decnergizesthe COL-B relay via the poles TRIP-8, REV-3, and COL-B-Z. The operatorcan now proceed the normal operation of changing one line by typing(recording) the corrected line of information.

After characters have been recorded, placing the carriage in the rightmargin, the operator depresses the TRIP key, which closes the tripswitch, thereby energizing the trip relay, via the pole RM3 (FIG. 2b).All trip poles transfer; a normal record operation trip takes place(erase current flows through the erase head, switch FSR-S, poles COL9and 120A9; FIG. 2a), except that the delay time of delay flop DF-4 is 20ms. instead of 633 ms., via the poles COL-6 and COLB-6 (FIG. 3a). Thecarriage is returned to the zero position and tape is advancedapproximately 0.06 inch. The recovery output of the delay flop DF-4restores the flip-flop FF-l via the pole RV-19 and the line 113, therebystopping the tape. The restore output of the flip-flop FF1 fires therelay reset thyratron, deenergizing the COL relay via the poles TRIP-8,SE7, and COL2. The pole COL-5 (FIG. 4b) deenergizes the RV relay,returning the RV poles to the verify function. The pole COL-8 transfersto normal, discharging the charged capacitor to energize the CR relay(FIG. 2b). The actuation of the pole CR-Q deenergizes the trip relay viathe poles TRIP- and SE1. The actuation of the pole CR-7 (FIG. 2c)energizes the REV relay. A normal verify carriage return operationresults. The operator then reverifies this blockette to make certainthat the information is recorded properly. After the blockette isreverified, the operator again performs a trip operation. The verifiernow reads the first character of the next blockette and the normalverify operation can be continued.

The comparator The comparator includes eight transformers Tl to TS,eight encoding switches, and two tab relays, TAB-A and TAB-B (FIG. 4d).The manner in which the comparator operates is determined by whether itis used as a bit-by-bit comparator or an odd-even checker. Thecomparator is shown in block form in FIG. 5. When the tab relays, TAB-Aand TAB-B, are deenergized, the comparator is connected for bit-by-hitcomparison. When these relays are energized, the comparator is connectedfor odd-even check.

Bit-by-bit check The poles of the TABA and TAB-B relays, in thedeenergized condition, connect the plate circuit of each of the eightmemory thyratrons to one end of the primary of the correspondingcomparator transformer. The other end of the primary of each transformeris connected to the corresponding encoding switch circuitry. The centertaps of the primaries of the transformers are connected in common to theprobe line through the pole RV-6.

In operation, the pulses are read from the tape and amplified, and theappropriate memory thyratrons are fired. When a thyratron conducts, thevoltage at its plate drops to a fixed level. This plate voltage droplowers the voltage at one end of the transformer primary. When thecorresponding encoding switch is closed, the voltage at the opposite endof the primary of the same comparator transformer is also dropped to thesame fixed voltage. The probe pulse (the recovery output of the delayflop DF5) is a 120 v. pulse. If the informa tion pulses are identical,that is, if equal voltage is applied to both ends of the transformer,there is current flow in equal and opposite directions in the primary ofthe comparator transformer, whereby no output occurs in the secondarywinding of the transformer. If the information pulses do not match, dueto incorrect voltage from either the encoding switch or the memorythyratron, current flows in one half of the primary of the comparatortransformer and a voltage develops in the secondary. An output in thesecondary of any of the comparator transformers fires the errorthyratron (FIG. 2a). All of the secondaries are connected in commonthrough diodes to the input of the error thyratron.

After each character is read and compared, the clear relay is energized.The clear relay changes the cathode connection of the memory thyratronfrom ground to 100 v. The memory thyratrons deionize. When a clear relayreturns to normal, the memory circuit is ready to receive anothercharacter for comparison.

Odd-even check During a fill operation, the TAB-A and TABB relays areenergized, converting the comparator to an odd-even checker. The poleTAB-AB-Z connects the plate of thyratron 5 to the primary of thetransformer Tl, pairing the channels 1 and 5 to transformer T-l. Thepole TABAB13 connects the plate of the thyratron 6 to the primary oftransformer T4, pairing the channels 2 and 6 to transformer TZ. The poleTABAB7 connects the plate of the thyratron 7 to the primary of thetransformer T3, pairing the channels 3 and 7 to the primary of thetransformer T 3. The pole TAB-AB12 connects the plate of thyratron 8 tothe primary of the transformer T4, pairing the channels 4 and 8. Thepole TAILAB- 11 disconnect the probe line from the transformers TS, T6,T7, and T8. The poles TAB-AB-3 and TAB- AB-4 connect the secondaries oftransformers T-l and TZ to the opposite ends of the primary oftransformer TS, pairing the outputs of the transformers Tl and TZ to theinput of the transformer TS. The poles TAB-AB8 and TAB-AB-9 connect thesecondaries of the transformers T3 and T4 to opposite ends of theprimary of transformer T6, pairing the outputs of the transformers T3and T4 to the input of the transformer T6. The poles TABAB5 and TABAB-6connect the secondaries of the transformers TS and T6 to opposite endsof the primary of the transformer T7, pairing the outputs oftransformers TS and T-6 to the input of the transformer T7. The poleTABAB17 connects the output of the transformer T7 to the primary of thetransformer TS. The pole TAB-AB-l9 connects the center tap of thetransformer T-8 to ground. The pole TAB-AB-13 converts the transformerT8 to a doubler. The pole TAB-AB-l disconnects the output of the transformers T1, T2, T3, T4, T5,'T-6, and T7 from the error thyratron.

As long as there is an even combination of bits there is no output. Whenan odd combination is present, an output develops and the errorthyratron fires, energizing the error relay.

Error In the verifier, there are two thyratrons (FIG. 2a) which initiatethe operation of the error circuitry. The error thyratron is used todetect comparator and oddeven errors. The error thyratron is used todetect greater or less than 120 errors.

The error thyratron grid is connected to the output of the comparator(FIGS. 5 and 6). The error thyratron shield is connected to the setoutput of the delay fiop DF-7; thus, whenever the delay flop DF-7 isset, the error thyratron is alerted. The cathodes of the error and 120error thyratrons are grounded only during the cycle of the verifyoperation via the pole RV-7. The plate voltage of the error thyratron issupplied through the pole REV-2 and the error relay. The plate voltageof the 120 error thyratron is also supplied through the pole REV2 andthe error relay except during a trip operation or when the carriage isin the zero or one position. During a trip operation or when thecarriage is in the zero or one position, the plate voltage is suppliedto the 120 error thyratron through the pole CR9, relay 120-A, and eitherthe pole TRIP-3 (during a trip operation) or a positioned switch LMX(when the carriage is in the zero or one position).

The 120 error thyratron is alerted only when the flipflop FF-! is setand the tape is moving. In a less-than- 120 error a pulse should bepresent and is not; in a greaterthan-12D error, a pulse is present wherethere should be none.

Comparator error during normal type A comparator error during normaltype, in brief, occurs as follows:

The print action switch PAS sets the delay flop DF-S via the line 116.

The recovery output of the delay flop DF-S probes the comparator via thepole RV-6 and alerts the error thyratron via the delay flop DF-7.

The comparator, upon detecting an error, fires the error thyratron. Theerror thyratron energizes the error relay. The error relay jams thefliptiop FF-l to the restore condition via the poles ERR6 and ERR-9 andlocks all keys via the pole ERR-2 (FIG. 20) except the BS, 120 CRCT, andCR. The operator performs a backspace operation which deenergizes theerror relay by way of the open pole REV-2 (FIG. 2a). The carriage isstepped back one position and the incorrect character is again read intothe memory.

More particularly, when a character is typed, the print action switchPAS (FIG. 2b) closes and remains closed approximately 35 ms. A pulse istransmitted thereby via the line 116 to set the delay flop DF-S. Fourmilliseconds after the print action switch PAS closes, a probe pulse isgenerated by the recovery of the delay flop DF-5. The recovery output ofthe delay flop DF- is coupled via the delay flop DF-7 to alert the errorthyratron. The recovery output of the delay flop DF5 is coupled via thepole RV-6 to probe the comparator so that if the information pulses readfrom the tape are not identical with the pulses generated by thekeyboard, the probe pulse generates an output from the comparator. Thisoutput from the comparator is coupled to the error thyratron, and, incoincidence with its alert pulse, fires the error thyratron. The firingof the error thyratron energizes the error relay by grounding one end ofthe relay coil. The poles of the error relay function as follows: thepole ERR-1 disables the trip switch (FIG. 2b); the pole ERR-2 locks thekeyboard (FIG. 2c); the pole ERR-3 disables the trip unlock actuator(FIG. 4 the pole ERR-6 prevents the setting of the flip-flop FF-l; thepole ERR-7 deenergizes the backspace lock actuator, freeing the BS key;the pole ERR9 jams the flip-flop FF-l to restore position, preventingthe tape from moving.

At this time all keys except the 120 CRCT and CR and BS are locked. Theflip-flop FF-l is jammed and restored, and the tape cannot move untilthe error relay is deenergized. The only way the error relay can bedeenergized is to energize the reverse relay. When the reverse relay isenergized, the transfer of the pole REV-2 (FIG. 2a) removes the platevoltage from the error relay. When the error relay is deenergized, theflip-flop FF-l restore-jam is removed and the tape is free to move. Theoperator now performs a backspace operation. (If the operator chooses todepress the 120 CRCT key or CR key, upon depressing the key, the errorrelay deenergizes and a carriage return is accomplished. The operator,then, would have to verify this blockette up to the point where theerror occurred.) A backspace operation energizes the REV relay (FIG. 20)and the pole REV-2 deenergizes the error relay which removes thejam-restore from the flip-flop FF1. The tape and carriage are steppedback one character position. The tape then moves forward and reads thecharacter back into the memory.

Odd-even error When a fill operation is initiated, the tab relays areenergized to connect the comparator so that it checks for odd-evenerrors. When an odd-even error is detected, the carriage continues tothe tab stop. The operator must perform a 120 correct operation,returning tape and carriage to the beginning of the blockette, and thenperform a change-one-line operation.

Assume, for example, the following conditions: the carriage is in zeroposition, the first character of the blockette is in the memory, the 10tab stop is set, and the fifth character contains an odd-even error. Theoperator depresses the fill key, initiating a verify fill operation withthe result that fill is normal until the fifth character is read intothe memory. The fifth character generates a pulse via the poles REV7 andCR-6 to set the delay flop DF-l, setting the delay fiop DF-Z, whichrestores the flip-flop FF1 via the line 113, and sets the delay flopDF-S. The recovery of the delay flop DF-S probes the comparator via thepole RV-6, and sets the delay flop DF7, alerting the error thyratron.The fifth character, containing an oddeven error, causes the comparatorto produce an output which fires the error thyratron.

The error thyratron, as described above, energizes the error relay sothat the pole ERR-1 disables the trip switch (FIG. 2b); the pole ERR-2locks the keyboard (FIG. 2c); the pole ERR-3 disables the trip unlockactuator (FIG. 4f); the pole ERR-6 prevents the setting of the flip-flopFF-l; the pole ERR-7 deenergizes the backspace lock actuator, freeingthe BS key; and the pole ERR-9 jams the flip-flop FF-l to restoreposition, preventing the tape from moving The tape is now stopped, butthe carriage continues to the tenth carriage position. When the carriagereaches the tenth position, the tab blade stops the carriage and returnsthe tab poles to normal. A not-equal indicator (not shown) lights,indicating that an error was detected during fill. The operatordepresses the correct key. The 120 correct switch transfers, energizingthe CR actuator to return the carriage to zero and energizing the CRrelay to return the tape to the beginning of the blockette. Transfer ofthe pole CR7 energizes the REV relay (FIG. 20). When the REV relay poleis transferred, the pole REV-2 (FIG. 2a) removes plate voltage from theerror thyratron, deenergizing the error relay. The deenergizetion of theerror relay, via the pole ERR-9, removes the jam on the flip-flop FF-land a normal verify carriage return takes place. At the completion ofthe carrriage return, the tape and carriage are synchronized, that is,the carriage is at zero position and the first character of theblockette is in the memory. The operator now performs a change-one-lineoperation.

An odd-even error during skip fill is similar to an oddeven error duringfill except that the carriage moves to the 120 position instead of tothe first tab stop.

Less-than-IZO error A blockette that has one or more characters missingis detected as a less-than-lZO error. Assume that the 120 characterposition is missing. When the operator types the 119 position character,the return of the print action switch PAS clears the memory via thelines 111 and I12 and sets the delay flop DF6. The recovery of the delayflop DF-6 sets the flip-fiop FF1, causing the tape to move forward,searching for the 120 position character. The set output of theflip-flop FF1, via the line 110, alerts the 120 error thyratron and, viathe poles CR-l and TRIP-6, sets the resettable delay flop RDF. After 10ms., the resettable delay flop RDF recovers, firing the 120 errorthyratron, via the pole CR-3.

The 120 error thyratron energizes the error relay via the pole TRIP3 andthe switch LMX with the following results: the pole ERR1 disables thetrip switch (FIG. 2b); the pole ERR-2 locks the keyboard (FIG. 20); thepole ERR3 disables the trip unlock actuator (FIG. 4]); the pole ERR-6prevents the setting of the flip-flop FF1; the pole ERR7 deenergizes thebackspace lock actuator, freeing the BS key; the ole ERR9 jams the Hipflop FF-l to restore position, preventing the tape from movmg.

At this time, the carriage is in the 120 position, the tape is stoppedapproximately 0.03 inch beyond the 119 position character, the flip-flopFF-1 is jammed-restored, the less-than-l20 error indicator (FIG. 2a) ison via the pole 120A2, and all keys are locked except the 120 CRCT key.The operator depresses the 120 CRCT key actuating the 120 correct switchwhich pulses the CR actuator (FIG. 2b) returning the carriage to thezero position, and energizing the CR relay. The CR relay energizes theREV relay via the pole CR-7 (FIG. 2c). The pole REV-2 (FIG. 2a)deenergizes the error relay, removing the restore jam on the flip-flopFF1 via the pole ERR-9. The pole REV2 sets the delay flop DF3. From thisoccurrence, a normal return of carriage and tape take place. Thecarriage returns to the zero position and the first character of theblockette is read into the memory. The tape and carriage are againsynchronized. The operator can now perform a change-one-line operationand rerecord the blockette.

If a character at the beginning of a blockette were missing, a normalcomparison error would be detected; the tape and carriage would be outof step.

1. A DEVICE FOR PREPARING A VERIFIED TAPE OF DATA INCLUDING INITIALLYPERFORMING THE OPERATION OF RECORDING DATA ONTO MAGNETIC TAPE AND FORSUBSEQUENTLY PERFORMING THE OPERATION OF VERIFYING DATA RECORDED ONMAGNETIC TAPE COMPRISING, IN COMBINATION, A TAPE DRIVING MECHANISM FORSTARTING AND STOPPING THE MOTION OF SAID TAPE; A PLURALITY OF MAGNETICHEADS FOR READING AND WRITING DATA UPON SAID TAPE; A TYPEWRITER KEYBOARDHAVING A PLURALITY OF KEYS; SELECTED CONTACTS CONNECTED TO SAID KEYSWHICH ARE OPERATIVE IN RESPONSE TO THE ACTUATION OF ANY OF SAID KEYS TOREPRODUCE A DIFFERENT ASSOCIATED CHARACTER ACCORDING TO SAID KEY; MEANSOPERATIVE DURING A RECORDING OPERATION RESPONSIVE TO THE ACTUATION OFSAID CONTACTS FOR STARTING THE MOTION OF SAID TAPE, FOR CAUSINGAPPROPRIATE ONES OF SAID HEADS CORRESPONDING TO SAID CONTACTS TO RECORDDATA UPON SAID TAPE, AND FOR STOPPING SAID TAPE, IN THE ORDER NAMED; AMEMORY; A COMPARATOR; MEANS OPERATIVE DURING A VERIFYING OPERATION FORENTERING INFORMATION INTO SAID COMPARATOR, FOR READING A CHARACTER FROMSAID TAPE, FOR STORING SAID CHARACTER IN SAID MEMORY, AND FOR STOPPINGTHE MOTION OF SAID TAPE, IN THE ORDER NAMED; SAID COMPARATOR ACTING TODIRECTLY COMPARE THE REPRESENTATION OF A CHARACTER STORED IN SAID MEMORYWITH THE REPRESENTATION OF A CHARACTER REPRESENTED BY THE OPERATION OFSAID SELECTED CONTACTS; MEANS RESPONSIVE TO THE ACTUATION OF ONE OF SAIDKEYS FOR STARTING THE MOTION OF SAID TAPE; AND MEANS RESPONSIVE TO ANONCOMPARISON FOR PREVENTING THE ACTUATION OF SAID KEYS.